On Tue, Aug 22, 2017 at 11:21:41AM +0200, Peter Zijlstra wrote: > On Tue, Aug 22, 2017 at 05:51:00PM +0900, Byungchul Park wrote: > > On Tue, Aug 22, 2017 at 09:52:38AM +0200, Peter Zijlstra wrote: > > > That wouldn't work. That annotation is to help find deadlocks like: > > > > > > > > > mutex_lock(&A) > > > <work> > > > mutex_lock(&A) > > > > > > flush_work(&work) > > > > > > > I meant: > > > > mutex_lock(&A) > > <work> > > lockdep_map_acquire_read(&work) > > mutex_lock(&A) > > > > lockdep_map_acquire(&work) > > flush_work(&work) > > > > I mean it can still be detected with a read acquisition in work. > > Am I wrong? > > Think so, although there's something weird with read locks that I keep > forgetting. But I'm not sure it'll actually solve the problem. But I can
I mean, read acquisitions are nothing but ones allowing read ones to be re-acquired legally, IOW, we want to check entrance of flush_work() and works, not between works. That's why I suggested to use read ones in work in that case.
